Electro-Thermal Transport in Nanotube Based Composites for Macroelectronic Applications

Kumar, Satish, M.S.E., Purdue University, December, 2007. Electro-Thermal Transport in Nanotube Based Composites for Macro-Electronic Applications. Major Professors: Muhammad A. Alam and Jayathi Y. Murthy. Dispersions of particles of different shapes and sizes in fluids or solids modify the transport properties of the underlying matrix. A remarkable enhancement in the electrical, thermal and other transport properties of the matrix due to the long aspect ratio dispersions like nanotube/nanowires has been observed my many research groups. This has motivated tremendous research to explore these composites for various macroelectronic and micro-electronic applications in the last decade. Carbon nanotubes (CNTs) network based thin-film transistors (TFTs) promise improved performance for flexible plastic electronics with potential applications in displays, e-paper, e-clothing, biochemical sensing, conformal radar, and others. A detailed theoretical and numerical framework is required to understand the functioning of the CNT network transistors and to interpret different experimental observations. In the present work we develop a computational model based on the classical transport equations to analyze the electro-thermal transport in isotropic 2D nanotube-net (Nanonet) based TFTs. We represent the Nanonet as a simple, two-dimensional, interpenetrating percolating network of metallic and semiconducting nanosticks. The methodology couples the electrical and thermal transport in an efficient and selfconsistent manner. We show the effect of electro-thermal coupling on device performance and explore temperature rise as a function of different parameters like channel length (LC), network density (ρ), tube-to-substrate thermal conductance (BiS), and tube-to-substrate thermal conductivity ratio.